1. Field of Invention
The present invention relates to an electronic heat dissipating device, and more particularly to a flat radiator with heat pipe and centrifugal fan for using in portable electronic devices, such as for cooling the electronic chips (CPU or GPU) in portable (notebook) computer.
2. Description of Related Arts
As the higher demands of thinner and multi-functional portable devices, especially the CPU and GPU, the thermal design for the heat dissipating of the whole system has become a bottleneck to the improvement of portable computer's performance. The radiator affixed to the CPU or GPU is like the shell on a snail, and it has occupied quite much room of the portable computer, so cutting down the thickness of portable computer is restricted by the radiator.
The structure of the radiator of current notebook computer is as follows. It has a centrifugal fan with a shell, which is usually a helicoid shaped shell and has a centralized air outlet. The air convective extended heat exchange surface, which is usually a fin structure, briefly called fin, is located at the air outlet. Usually heat pipes are used to transport the heat produced by the CPU to the fin.
The disadvantages of this design include the followings. First, the air outlet is easily blocked, it will cause that the heat can't be dissipated. Second, the wind driven by the fan is directly vented after flowing through the fin, and is unable to be further utilized. Next, the shell of the fan takes up much room of the fan, so that in order to reduce the volume, the shape of the shell isn't standard helicoid shape, which results in much more air vortex loss, and asymmetrical air flow at the air outlet, and it is unbeneficial for heat dissipation. Last, because of the restriction of the line layout, the CPU should be located near the center of the motherboard, so that the distance between the fin and the CPU is so long that long heat pipes are needed, and the distance between the vaporizing area and the condensing area of the heat pipe is longer, and the heat transport capacity becomes less.
Due to the heat dissipation of the CPU and GPU, no standardization of the notebook radiator has been formed, and the inner structure of notebook is also diversified. Different series of notebook have different structures, even the same series have different structures just because of the problem of the heat dissipation. It increases much more cost to the notebook, while its performance can not compare with the desktop computer. It also restricts people to extend their devices like the desktop computer.